JP2015019450A - Non-contact power transmission device, power transmission apparatus, power reception apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission device, a power transmission apparatus and a power reception apparatus, capable of calculating the degree of a power loss in consideration of the power loss of a DC/AC converter unit.SOLUTION: A non-contact power transmission device 10 includes: a power supply unit 12 capable of converting, when system power is input, the system power into AC power having a preset frequency to output; a primary side coil 13a to which the AC power is input; a secondary side coil 23a capable of receiving the AC power from the primary side coil 13a in a non-contact manner; a rectifier 24 for rectifying the AC power received by the secondary side coil 23a; and a vehicle battery 22. In the above configuration, a vehicle side controller 25 calculates efficiency on the basis of a primary side DC power value P0 and a secondary side DC power value P1.

Description

  The present invention relates to a non-contact power transmission device, a power transmission device, and a power reception device.

  As a non-contact power transmission device that does not use a power cord or a power transmission cable, for example, a power transmission device having a primary coil to which AC power is input and a secondary side that can receive AC power in a non-contact manner from the primary coil What is provided with the power receiving apparatus which has a coil is known (for example, refer patent document 1). In such a non-contact power transmission device, AC power is transmitted from a power transmitting device to a power receiving device in a non-contact manner, for example, by magnetic resonance between the primary side coil and the secondary side coil. The AC power transmitted from the power transmitting device to the power receiving device is rectified into secondary DC power. The secondary DC power is used for charging the vehicle battery.

  Further, for example, the non-contact power transmission device described in Patent Document 2 includes a power supply unit that outputs AC power having a predetermined frequency, and is received by the power value of the AC power output from the power supply unit and the power receiving device. The degree of power loss is calculated based on the power value of the AC power.

JP 2009-106136 A International Publication No. 2011/061821

  Here, the power supply unit normally includes an AC / DC conversion unit that converts system power into primary DC power and a DC / AC conversion unit that converts primary DC power into AC power. In this case, as shown in Patent Document 2, in the configuration in which the degree of power loss is calculated based on the measurement result of the power value of the AC power output from the power supply unit, The power loss due to the AC converter is not considered. For this reason, a deviation may occur between the calculated degree of power loss and the degree of power loss considering the power loss of the DC / AC converter. Then, for example, in a configuration in which various processes are performed based on the degree of power loss, an incorrect process may be performed. Further, when some abnormality occurs in the DC / AC conversion unit, the power loss of the DC / AC conversion unit may increase. In this case, if it is determined whether or not the non-contact power transmission apparatus is normal based on the calculated degree of power loss, it is mistaken for normality even though the DC / AC converter is abnormal. Can happen.

  The present invention has been made in view of the above-described circumstances, and provides a non-contact power transmission device, a power transmission device, and a power reception device capable of calculating the degree of power loss in consideration of the power loss of the DC / AC conversion unit. The purpose is to provide to do.

  The non-contact power transmission device that achieves the above object includes a power supply unit capable of converting the grid power into AC power having a predetermined frequency when grid power is input from a grid power supply, and the AC A primary coil to which power is input, a secondary coil capable of receiving the AC power from the primary coil in a non-contact manner, and a rectifying unit for rectifying the AC power received by the secondary coil; And a load to which secondary DC power rectified by the rectifier is input, and the power supply unit converts the system power into predetermined primary DC power. And a DC / AC converter that converts the primary-side DC power into the AC power, and the non-contact power transmission device includes power of the primary-side DC power that is input to the DC / AC converter. A primary side measuring unit for measuring a value; Based on the secondary side measurement unit that measures the power value of the secondary side DC power at a predetermined position from the flow unit to the load, the measurement result of the primary side measurement unit, and the measurement result of the secondary side measurement unit And a calculating unit that calculates the degree of power loss from the input end of the DC / AC converting unit to the predetermined position.

  According to this configuration, based on the power value of the primary DC power input to the DC / AC converter and the power value of the secondary DC power at a predetermined position from the rectifier to the load, The degree of power loss from the input end of the AC converter to a predetermined position is calculated. The degree of the power loss includes the power loss of the DC / AC converter. Thereby, the degree of power loss considering the power loss of the DC / AC converter can be calculated.

  For the non-contact power transmission device, an impedance conversion unit provided between the power supply unit and the load and having a variable impedance, and variable control of impedance of the impedance conversion unit based on a calculation result of the calculation unit. And a controller for performing the operation. According to this configuration, by performing variable control of the impedance of the impedance conversion unit based on the calculated degree of power loss, variable control of the impedance of the impedance conversion unit considering the power loss of the DC / AC conversion unit is performed. It can be carried out. Thereby, compared with the said variable control based on the degree of the power loss which does not consider the power loss of a DC / AC conversion part, the said variable control can be performed more suitably.

  For the non-contact power transmission apparatus, the secondary side measurement unit measures the power value of the secondary side DC power at the position of the input end of the load as the predetermined position, and the calculation unit includes: The degree of power loss from the input end of the DC / AC converter to the load may be calculated based on the measurement result of the primary side measurement unit and the measurement result of the secondary side measurement unit. According to this configuration, the power value of the secondary side DC power at the position of the input end of the load is measured, and the degree of power loss from the input end of the DC / AC converter to the load is calculated. Thereby, the degree of power loss considering the power loss of the DC / AC conversion unit and the power loss from the power source unit to the load is calculated. Therefore, it is possible to calculate the degree of power loss of the entire contactless power transmission apparatus excluding the power loss of the AC / DC converter.

  A power transmission device that achieves the above object includes a power supply unit that, when system power is input from a system power supply, converts the system power into AC power having a predetermined frequency and outputs the power, and the AC power is input A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil, a rectifier that rectifies the AC power received by the secondary coil, and For the power receiving device having a load to which the secondary side DC power rectified by the rectifying unit is input, the AC power can be transmitted in a contactless manner, and the power source unit supplies the grid power, An AC / DC converter that converts the primary DC power to a predetermined primary DC power; and a DC / AC converter that converts the primary DC power into the AC power. The power transmission device includes the DC / AC The primary input to the converter A primary side measuring unit that measures the power value of the DC power, and the measurement result of the primary side measuring unit and the power value of the secondary side DC power at a predetermined position from the rectifying unit to the load, The degree of power loss from the input end of the DC / AC converter to the predetermined position is calculated.

  According to this configuration, based on the power value of the primary DC power input to the DC / AC converter and the power value of the secondary DC power at a predetermined position from the rectifier to the load, The degree of power loss from the input end of the AC converter to a predetermined position is calculated. The degree of the power loss includes the power loss of the DC / AC converter. Thereby, the degree of power loss considering the power loss of the DC / AC converter can be calculated.

  The power transmission device includes an impedance conversion unit that is provided between the power supply unit and the primary side coil and has a variable impedance. Based on the calculated degree of power loss, the impedance of the impedance conversion unit Variable control may be performed. According to this configuration, by performing variable control of the impedance of the impedance conversion unit based on the calculated degree of power loss, variable control of the impedance of the impedance conversion unit considering the power loss of the DC / AC conversion unit is performed. It can be carried out. Thereby, compared with the said variable control based on the degree of the power loss which does not consider the power loss of a DC / AC conversion part, the said variable control can be performed more suitably.

  The power receiving device that achieves the above object includes an AC / DC converter that converts the grid power to a predetermined primary DC power when the grid power is input from the grid power supply, and the primary DC power The AC power is received in a non-contact manner from a power transmission device having a DC / AC converter that converts AC into AC power having a predetermined frequency and a primary coil to which the AC power is input. A secondary coil capable of receiving the AC power from the primary coil in a non-contact manner; a rectifier that rectifies the AC power received by the secondary coil; and the rectifier A load to which the secondary side DC power rectified by the input is input, and a secondary side measurement unit that measures a power value of the secondary side DC power at a predetermined position from the rectification unit to the load, Input to DC / AC converter The degree of power loss from the input end of the DC / AC converter to the predetermined position is calculated based on the power value of the primary side DC power and the measurement result of the secondary side measuring unit. And

  According to this configuration, based on the power value of the primary DC power input to the DC / AC converter and the power value of the secondary DC power at a predetermined position from the rectifier to the load, The degree of power loss from the input end of the AC converter to a predetermined position is calculated. The degree of the power loss includes the power loss of the DC / AC converter. Thereby, the degree of power loss considering the power loss of the DC / AC converter can be calculated.

  The power receiving device includes an impedance conversion unit that is provided between the secondary coil and the load and has a variable impedance, and the impedance of the impedance conversion unit is variable based on the calculated degree of power loss. Control should be performed. According to this configuration, by performing variable control of the impedance of the impedance conversion unit based on the calculated degree of power loss, variable control of the impedance of the impedance conversion unit considering the power loss of the DC / AC conversion unit is performed. It can be carried out. Thereby, compared with the said variable control based on the degree of the power loss which does not consider the power loss of a DC / AC conversion part, the said variable control can be performed more suitably.

  According to the present invention, it is possible to calculate the degree of power loss in consideration of the power loss of the DC / AC converter.

The block circuit diagram which shows the electric constitution of the non-contact electric power transmission apparatus of 1st Embodiment. The flowchart which shows the charging process performed in cooperation with each controller. The block circuit diagram which shows the electric constitution of the non-contact electric power transmission apparatus of 2nd Embodiment. The flowchart which shows the charging process performed in cooperation with each controller.

(First embodiment)
Hereinafter, a first embodiment in which a non-contact power transmission device (non-contact power transmission system), a power transmission device (power transmission device), and a power reception device (power reception device) are applied to a vehicle will be described.

  As shown in FIG. 1, the non-contact power transmission device 10 includes a power transmission device 11 (ground side device, primary side device) and a power receiving device 21 (vehicle side device, secondary side device) capable of non-contact power transmission. It has. The power transmission device 11 is provided on the ground, and the power receiving device 21 is mounted on the vehicle.

  The power transmission device 11 includes a power supply unit 12 that can output AC power having a predetermined frequency when system power is input. The power supply unit 12 is configured to be able to convert the grid power to AC power and output the converted AC power when grid power is input from the grid power supply E as infrastructure.

  Specifically, the power supply unit 12 includes an AC / DC converter 12a that converts system power into predetermined primary DC power. The AC / DC converter 12a is configured by, for example, a PFC circuit having a first switching element 12aa that periodically performs an on / off operation. When system power is input, the AC / DC converter 12a converts the system power into primary DC power while improving the power factor, and outputs the primary DC power.

  The power supply unit 12 includes a DC / AC converter 12b (DC / AC conversion unit) that converts primary-side DC power output from the AC / DC converter 12a into AC power. The DC / AC converter 12b includes, for example, a second switching element 12bb that periodically performs a switching operation. The DC / AC converter 12b converts the DC power into AC power by the second switching element 12bb performing a switching operation, and outputs the converted AC power.

  In addition, as each switching element 12aa and 12bb, IGBT, power MOSFET, etc. are used, for example. As a specific configuration of the DC / AC converter 12b, for example, a class D amplifier, a class E amplifier, or the like can be considered.

  The AC power output from the power supply unit 12 is transmitted to the power receiving device 21 in a non-contact manner and used for charging the vehicle battery 22 as a load provided in the power receiving device 21. Specifically, the non-contact power transmission apparatus 10 performs power transmission between the power transmission device 11 and the power reception device 21, and includes a power transmitter 13 provided in the power transmission device 11 and a power receiver provided in the power reception device 21. 23.

  The power transmitter 13 and the power receiver 23 have the same configuration, and both are configured to be capable of magnetic field resonance. Specifically, the power transmitter 13 includes a resonance circuit including a primary coil 13a and a primary capacitor 13b connected in parallel. The power receiver 23 has a resonance circuit including a secondary coil 23a and a secondary capacitor 23b connected in parallel. Both resonance frequencies are set to be the same.

  According to such a configuration, when AC power is input to the power transmitter 13 (primary coil 13a) in a situation where the relative position between the power transmitter 13 and the power receiver 23 is in a position where magnetic resonance can occur, The power receiver 23 (secondary coil 23a) performs magnetic field resonance. As a result, the power receiver 23 receives a part of the energy of the power transmitter 13. That is, the power receiver 23 receives AC power from the power transmitter 13.

  Incidentally, the frequency of the AC power output from the power supply unit 12 is set corresponding to the resonance frequency of the power transmitter 13 and the power receiver 23 so that power transmission is possible between the power transmitter 13 and the power receiver 23. Yes. For example, the frequency of AC power is set to be the same as the resonance frequency of the power transmitter 13 and the power receiver 23. In addition, it is not restricted to this, The frequency of alternating current power and the resonant frequency of the power transmission device 13 and the power receiving device 23 may have shifted | deviated within the range which can be transmitted.

  The power receiving device 21 includes a rectifier 24 (rectifying unit) that rectifies AC power received by the power receiver 23. The secondary DC force rectified by the rectifier 24 is input to the vehicle battery 22, whereby the vehicle battery 22 is charged.

  The power transmission device 11 includes a power supply side controller 14 that controls the power supply unit 12 and the like. The power supply side controller 14 controls whether or not AC power is output from the power supply unit 12 by performing switching control of the switching elements 12aa and 12bb.

  The power receiving device 21 includes a vehicle-side controller 25 configured to be capable of wireless communication with the power-side controller 14. The controllers 14 and 25 start or end power transmission through the exchange of information with each other. Each controller 14 and 25 corresponds to a control unit.

  The power receiving device 21 includes an SOC sensor 26 that detects the SOC (charged state) of the vehicle battery 22. The SOC sensor 26 sequentially transmits the SOC of the vehicle battery 22 to the vehicle-side controller 25. Thereby, the vehicle-side controller 25 can grasp the SOC of the vehicle battery 22.

  As shown in FIG. 1, the non-contact power transmission device 10 includes a plurality of impedance converters 31 and 32 (matching unit, impedance conversion unit) provided between the power supply unit 12 and the vehicle battery 22. . Specifically, the non-contact power transmission apparatus 10 includes a first impedance converter 31 (first impedance converter) provided in the power transmission device 11 and a second impedance converter 32 (second second) provided in the power receiving device 21. Impedance conversion unit). Each impedance converter 31 and 32 is comprised by LC circuit which has an inductor and a capacitor, for example. The first impedance converter 31 corresponds to the primary side impedance converter, and the second impedance converter 32 corresponds to the secondary side impedance converter.

  The first impedance converter 31 is provided between the power supply unit 12 and the power transmitter 13, and AC power output from the power supply unit 12 is input to the power transmitter 13 via the first impedance converter 31 ( Transmission). The first impedance converter 31 impedance-converts the input impedance of the power transmitter 13 so that the output impedance of the power supply unit 12 matches the input impedance of the first impedance converter 31. The input impedance of the first impedance converter 31 is the impedance from the input end of the first impedance converter 31 to the vehicle battery 22, and the input impedance of the power transmitter 13 is from the input end of the power transmitter 13. This is the impedance to the vehicle battery 22.

  The second impedance converter 32 is provided between the power receiver 23 and the vehicle battery 22, specifically between the power receiver 23 and the rectifier 24, and the AC power received by the power receiver 23 is The signal is input to the rectifier 24 via the two impedance converter 32. The second impedance converter 32 changes the input impedance of the rectifier 24 so that the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 matches the impedance from the output terminal of the power receiver 23 to the power supply unit 12. Convert.

  Each of the impedance converters 31 and 32 is configured such that a constant (impedance) is variable. Specifically, at least one of the inductance of the inductor and the capacitance of the capacitor constituting the first impedance converter 31 is variable. Similarly, at least one of the inductance of the inductor and the capacitance of the capacitor constituting the second impedance converter 32 is variable. The constant can be said to be a conversion ratio, or an inductance or a capacitance.

  Here, power loss occurs due to the second switching element 12bb of the DC / AC converter 12b performing a switching operation. On the other hand, the non-contact power transmission apparatus 10 of the present embodiment takes into consideration the power loss of the DC / AC converter 12b, and the power loss from the input end of the DC / AC converter 12b to the vehicle battery 22 The structure which calculates the degree of is provided. Hereinafter, a configuration related to the calculation of the degree of power loss will be described.

  As shown in FIG. 1, the power transmission device 11 of the non-contact power transmission apparatus 10 measures a primary side DC power value P0 that is a power value of the primary side DC power input to the DC / AC converter 12b. A secondary measuring instrument 40 (primary measuring unit) is provided. The primary-side measuring device 40 is provided between the AC / DC converter 12a and the DC / AC converter 12b, and calculates the primary-side DC power value P0 at the input end of the DC / AC converter 12b. The measurement result is transmitted to the power supply controller 14. In addition, it can be said that the primary side measuring device 40 measures the primary side direct-current power value P0 in the position of the output terminal of the AC / DC converter 12a.

  The power receiving device 21 includes a secondary-side measuring device 50 (secondary-side measuring unit) that measures a secondary-side DC power value P1 that is a power value of the secondary-side DC power at a predetermined position from the rectifier 24 to the vehicle battery 22. ). The secondary measuring instrument 50 is provided between the rectifier 24, which is a subsequent stage of the rectifier 24, and the vehicle battery 22. The secondary-side measuring instrument 50 measures the power value of the AC power input to the vehicle battery 22, that is, the secondary-side DC power value P1 at the position of the input end of the vehicle battery 22, and the measurement result is measured on the vehicle side. It transmits to the controller 25.

  When the power transmission device 11 and the power reception device 21 are arranged at positions where power can be transmitted, the controllers 14 and 25 of the non-contact power transmission apparatus 10 exchange information between the two and synchronize with each other. A series of charging processes for charging the battery 22 is performed.

  Here, when the relative positions of the coils 13 a and 23 a and the impedance of the vehicle battery 22 vary, impedance mismatch may occur in the power transmitting device 11 and the power receiving device 21. On the other hand, in the charging process, the controllers 14 and 25 perform variable control of the constants of the impedance converters 31 and 32 based on the measurement results of the measuring instruments 40 and 50. Hereinafter, the charging process will be described in detail.

  As shown in FIG. 2, first, in step S <b> 101, the power supply controller 14 controls the switching elements 12 aa and 12 bb so that AC power is output from the power supply unit 12. Thereby, AC power is transmitted from the power supply unit 12 toward the vehicle battery 22.

  Thereafter, in steps S102 to S107, the controllers 14 and 25 calculate efficiency η, which is a type of parameter indicating the degree of power loss from the input end of the DC / AC converter 12b to the vehicle battery 22, and Then, variable control of the constants of the impedance converters 31 and 32 based on the efficiency η is performed.

  Specifically, first, in step S102, the power supply side controller 14 grasps the primary side DC power value P0 using the primary side measuring device 40, and the vehicle side controller 25 uses the secondary side measuring device 50. Thus, the secondary side DC power value P1 is grasped.

  Thereafter, in step S <b> 103, the power supply controller 14 transmits information related to the primary DC power value P <b> 0 to the vehicle controller 25. The vehicle side controller 25 grasps the primary side DC power value P0 by receiving the information.

  In subsequent step S104, the vehicle-side controller 25 calculates the efficiency η based on the primary side DC power value P0 and the secondary side DC power value P1. The efficiency η is a value obtained by dividing the secondary side DC power value P1 by the primary side DC power value P0 (η = P1 / P0). In the present embodiment, the vehicle-side controller 25 corresponds to the calculation unit.

  Here, for example, when a power loss rate (power reduction rate) X (= (P0−P1) / P0) is defined as a parameter indicating the degree of power loss, X = 1−η. In this case, the efficiency η and the power loss rate X correspond one-to-one. That is, the calculation of the efficiency η can be said to be equivalent to the calculation of the power loss rate X from the input end of the DC / AC converter 12b to the vehicle battery 22.

  After calculating the efficiency η, the vehicle-side controller 25 compares the calculated efficiency η with a predetermined threshold efficiency ηx in step S105. Specifically, the vehicle-side controller 25 determines whether or not the calculated efficiency η is greater than or equal to the threshold efficiency ηx. If attention is paid to the relationship between the power loss rate X and the efficiency η, it can be said that the process of step S105 is a process of determining whether or not the calculated power loss rate X is equal to or less than a predetermined threshold loss rate. . That is, the process of step S105 can be said to be a process of determining whether or not the calculated degree of power loss is within a predetermined allowable range.

  When the calculated efficiency η is less than the threshold efficiency ηx, the controllers 14 and 25 perform variable control of the constants of the impedance converters 31 and 32. Specifically, the vehicle-side controller 25 makes a negative determination in step S105, and proceeds to step S106. In step S <b> 106, the vehicle-side controller 25 transmits information related to the calculated efficiency η to the power supply-side controller 14. Thereby, the power supply side controller 14 grasps the calculated efficiency η.

  Thereafter, in step S107, the controllers 14 and 25 perform variable control of the constants of the impedance converters 31 and 32 so that the efficiency η is increased based on the calculated efficiency η. Although the specific mode of the variable control is arbitrary, for example, the power supply side controller 14 calculates the first change amount based on the difference between the calculated efficiency η and the threshold efficiency ηx, and the calculation is performed. The constant of the first impedance converter 31 is changed by the first change amount. Similarly, the vehicle-side controller 25 calculates the second change amount based on the difference, and changes the constant of the second impedance converter 32 by the calculated second change amount.

  After variable control of the constants of the impedance converters 31 and 32 is performed in step S107, the process returns to step S102. That is, variable control of the constants of the impedance converters 31 and 32 is performed until the calculated efficiency η is equal to or greater than the threshold efficiency ηx.

  Focusing on the relationship between the power loss rate X and the efficiency η, each of the controllers 14 and 25 determines that the power loss rate X is equal to or less than the threshold loss rate when the calculated power loss rate X is higher than the threshold loss rate. Thus, it can be said that the variable control of the constants of the impedance converters 31 and 32 is performed. That is, when the calculated power loss level is outside the allowable range, the controllers 14 and 25 perform variable control of the constants of the impedance converters 31 and 32 so that the power loss level is within the allowable range. Is what you do.

  In addition, even if it is a case where the constant of each impedance converter 31 and 32 is set to which value, when the calculated efficiency (eta) does not become more than threshold efficiency (eta) x, it will stop charging processing as an error. Also good. “The calculated efficiency η does not exceed the threshold efficiency ηx” means that, for example, a metal foreign object exists between the coils 13a and 23a, the positional deviation of the coils 13a and 23a is outside the allowable range, and the like. It is done.

  When the calculated efficiency η is equal to or greater than the threshold efficiency ηx, it is not necessary to perform variable control of the constants of the impedance converters 31 and 32, or variable control of the constants of the impedance converters 31 and 32 is completed. Means that In this case, the vehicle-side controller 25 makes a positive determination in step S105 and proceeds to step S108.

  Here, in the present embodiment, the non-contact power transmission device 10 confirms whether or not power transmission is normally performed at a predetermined frequency while the vehicle battery 22 is being charged. Specifically, in step S108, each of the controllers 14 and 25 determines whether or not an adjustment start condition is satisfied. The adjustment start condition defines a confirmation timing for confirming whether or not power transmission is normally performed. The adjustment start condition may be, for example, a case where a predetermined time has elapsed since the start of charging of the vehicle battery 22 or a case where a predetermined time has elapsed since the previous confirmation. In the configuration in which the power value of the AC power output from the power supply unit 12 varies, a case where the power value of the AC power output from the power supply unit 12 varies may be set as the adjustment start condition.

  Note that the execution subject of the determination process in step S108 may be either the power supply controller 14 or the vehicle controller 25. Further, the determination processing in step S108 may be performed by the controllers 14 and 25 exchanging information with each other.

  If the adjustment start condition is satisfied, the process returns to step S102. In this case, the vehicle-side controller 25 cooperates with the power supply-side controller 14 to calculate the efficiency η and compare the efficiency η and the threshold efficiency ηx. The controllers 14 and 25 perform variable control of the constants of the impedance converters 31 and 32 when the efficiency η is lower than the threshold efficiency ηx.

  On the other hand, if the adjustment start condition is not satisfied, the vehicle-side controller 25 determines whether or not the charge end condition is satisfied in step S109. The charge termination condition may be, for example, a case where the SOC of the vehicle battery 22 is a predetermined termination trigger state, for example, 100%.

  When the charging end condition is satisfied, in step S110, the power supply side controller 14 stops the output of the AC power from the power supply unit 12, and ends this process. On the other hand, if the charge termination condition is not satisfied, the process returns to step S108 again.

  That is, the AC power is transmitted until the charging end condition is satisfied, and the efficiency η is calculated each time the adjustment start condition is satisfied during the transmission of the AC power. Variable control of the constants of the impedance converters 31 and 32 is performed.

Next, the operation of this embodiment will be described.
Efficiency is based on the primary side DC power value P0 that is the power value of the grid power input to the power supply unit 12, and the secondary side DC power value P1 that is the power value of the AC power input to the vehicle battery 22. η is calculated. Therefore, the efficiency η is a value considering the power loss of the DC / AC converter 12b. When the efficiency η is less than the threshold efficiency ηx, variable control of constants of the impedance converters 31 and 32 is performed so that the efficiency η is equal to or higher than the threshold efficiency ηx.

According to the embodiment described in detail above, the following excellent effects are obtained.
(1) The power transmission device 11 of the non-contact power transmission device 10 includes a power supply unit 12 capable of converting the grid power into AC power having a predetermined frequency and outputting the grid power when AC power is input, and AC power Is input to the power transmitter 13. The power supply unit 12 includes an AC / DC converter 12a that converts system power into predetermined primary DC power, and a DC / AC converter 12b that converts primary DC power into AC power. Yes. The power receiving device 21 of the non-contact power transmission apparatus 10 includes a power receiver 23 that can receive AC power in a non-contact manner from the power transmitter 13, a rectifier 24 that rectifies the AC power received by the power receiver 23, and a rectifier 24. And a vehicular battery 22 to which the secondary side DC power is input. In such a configuration, the power transmission device 11 includes a primary side measuring device 40 that measures the primary side DC power value P0 input to the DC / AC converter 12b, and the power receiving device 21 is connected to the vehicle from the output end of the rectifier 24. The secondary side measuring device 50 which measures the secondary side direct-current power value P1 in the predetermined position to the battery 22 for an operation is provided. Then, the vehicle-side controller 25 of the non-contact power transmission device 10 determines the degree of power loss from the input end of the DC / AC converter 12b to the predetermined position based on the measurement results of the measuring devices 40 and 50, and details. In this case, the efficiency η (power loss rate X) is calculated. Thereby, the efficiency η in consideration of the power loss in the power supply unit 12 can be calculated.

  Here, for example, as an example of determining whether to start power transmission or determining whether to continue power transmission, there is determination of whether the calculated efficiency is equal to or higher than the threshold efficiency ηx. In this case, when the above determination is performed based on the efficiency in which the power loss of the DC / AC converter 12b is not considered, the efficiency in consideration of the power loss of the DC / AC converter 12b is less than the threshold efficiency ηx. Regardless, there may occur a situation where the efficiency in which the power loss of the DC / AC converter 12b is not taken into consideration is equal to or higher than the threshold efficiency ηx. Then, power transmission is performed in a state where the efficiency considering the power loss of the DC / AC converter 12b is less than the threshold efficiency ηx, which may cause inconveniences such as an increase in power loss and an increased burden on the power supply unit 12.

On the other hand, in this embodiment, since the efficiency η is calculated in consideration of the power loss of the DC / AC converter 12b, the above inconvenience can be avoided.
In particular, the calculation of the efficiency based on the DC power values P0 and P1 is less than the configuration in which the efficiency is calculated based on the power value of the AC power, so that it is not necessary to measure the phase difference or the like. It is possible to simplify the configuration of the measuring devices 40 and 50 and facilitate efficiency calculation.

  In addition, compared with the AC power output from the power supply unit 12, the voltage waveform and current waveform of the primary side DC power are waveforms resulting from the impedance variation from the output terminal of the power supply unit 12 to the vehicle battery 22. It is difficult for adverse effects from the output side of the power supply unit 12 such as distortion and noise that may occur during non-contact power transmission. Thereby, in the calculation of efficiency η, the above-described adverse effect can be reduced, and the accuracy related to the calculation of efficiency η can be improved.

  (2) The non-contact power transmission apparatus 10 includes impedance converters 31 and 32 that are provided between the power supply unit 12 and the vehicle battery 22 and whose constants are variable. Then, the controllers 14 and 25 perform variable control of the constants of the impedance converters 31 and 32 based on the calculated efficiency η. Specifically, when the calculated efficiency η is less than the threshold efficiency ηx, the controllers 14 and 25 variably control the constants of the impedance converters 31 and 32 so that the efficiency η is equal to or higher than the threshold efficiency ηx. . Thus, the variable control can be more suitably performed by variably controlling the constants of the impedance converters 31 and 32 based on the efficiency η in consideration of the power loss of the DC / AC converter 12b.

  Specifically, for example, when the variable control is performed based on the efficiency not considering the power loss of the DC / AC converter 12b so that the efficiency becomes equal to or higher than the threshold efficiency ηx, the DC / AC converter 12b When the efficiency η considering the power loss is less than the threshold efficiency ηx, there may be a problem that the variable control is terminated. On the other hand, according to the present embodiment, the variable control is performed so that the efficiency η considering the power loss of the DC / AC converter 12b is equal to or higher than the threshold efficiency ηx. It is possible to avoid the inconvenience that the variable control is terminated in a state where η is not increased.

  (3) The secondary side measuring instrument 50 measures the secondary side DC power value P1 at the position of the input end of the vehicle battery 22 as a predetermined position. The vehicle-side controller 25 calculates the efficiency η from the input end of the DC / AC converter 12b to the vehicle battery 22. Thereby, the efficiency η of the entire non-contact power transmission device 10 excluding the power loss of the AC / DC converter 12a (the power conversion efficiency by the DC / AC converter 12b and the output terminal of the power supply unit 12 to the vehicle battery 22). The efficiency η) including the power transmission efficiency can be calculated. Therefore, the variable control of the constants of the impedance converters 31 and 32 based on the efficiency η of the entire contactless power transmission device 10 excluding the power loss of the AC / DC converter 12a can be performed, and the overall efficiency η can be controlled. Further improvement can be achieved.

  (4) The non-contact power transmission apparatus 10 includes two impedance converters 31 and 32 as impedance conversion units having a variable constant. Specifically, the power transmission device 11 includes a first impedance converter 31 provided between the power supply unit 12 and the power transmitter 13. The power receiving device 21 includes a second impedance converter 32 provided between the power receiver 23 and the rectifier 24. And each controller 14 and 25 performs variable control of the constant of each impedance converter 31 and 32 based on efficiency (eta). Thereby, the efficiency η can be further improved by reducing both the impedance mismatch in the power transmitting device 11 and the impedance mismatch in the power receiving device 21.

(Second Embodiment)
In the present embodiment, as shown in FIG. 3, the non-contact power transmission apparatus 10 outputs an output power measuring device 60 (output) that measures the power value of AC power output from the power supply unit 12 (hereinafter referred to as AC power value P2). Power measurement unit). The output power measuring device 60 is provided between the power supply unit 12 and the first impedance converter 31 in the power transmission device 11. The output power measuring device 60 measures the AC power value P <b> 2 at the position of the output end of the power supply unit 12 and transmits the measurement result to the power supply side controller 14.

  Here, the AC power value P <b> 2 depends on the impedance Zp from the output end of the power supply unit 12 to the vehicle battery 22. In such a configuration, the first impedance converter 31 impedance-converts the input impedance of the power transmitter 13 so that the AC power value P2 approaches (preferably matches) a predetermined specific power value Pt. Specifically, the impedance Zp from the output end of the power supply unit 12 to the vehicle battery 22 includes an impedance Zt at which the AC power value P2 becomes the specific power value Pt. The first impedance converter 31 performs impedance conversion so that the impedance Zp from the output end of the power supply unit 12 to the vehicle battery 22 approaches the impedance Zt. The specific power value Pt is, for example, an AC power value P <b> 2 for allowing the power value input to the vehicle battery 22 to be a power value suitable for charging the vehicle battery 22.

  Here, as already described, the efficiency η and the AC power value P2 vary according to the relative positions of the coils 13a and 23a. On the other hand, in the present embodiment, the vehicle-side controller 25 calculates the efficiency η in the charging process, and performs variable control of the constant of the second impedance converter 32 based on the calculation result. In addition, the power supply side controller 14 compares the AC power value P2 and the specific power value Pt in the charging process, and performs variable control of the constant of the first impedance converter 31 based on the comparison result.

  Hereinafter, the charging process of this embodiment will be described in detail with reference to FIG. In addition, since the process of step S201 and step S210-step S212 is the same as the corresponding process (process of step S101, step S108-step S110) of 1st Embodiment, description is abbreviate | omitted.

  As shown in FIG. 4, first, in step S201, the power supply side controller 14 starts outputting AC power. Thereafter, in Steps S202 to S209, the controllers 14 and 25 perform calculation of efficiency η and variable control of the constant of the second impedance converter 32 based on the calculation result, and AC output from the power supply unit 12 The power value P2 is confirmed and adjusted.

  Specifically, first, in step S202, the power supply side controller 14 uses the primary side measuring device 40 and the output power measuring device 60 to grasp the primary side DC power value P0 and the AC power value P2, and the vehicle side controller. 25 uses the secondary side measuring device 50 to grasp the secondary side DC power value P1.

  Thereafter, in step S203, the power supply side controller 14 transmits the primary side DC power value P0 to the vehicle side controller 25. In subsequent step S204, the vehicle-side controller 25 calculates the efficiency η. In step S205, the vehicle-side controller 25 determines whether or not the calculated efficiency η is greater than or equal to the threshold efficiency ηx.

  When the efficiency η is less than the threshold efficiency ηx, the process proceeds to step S206, and the vehicle-side controller 25 performs variable control of the constant of the second impedance converter 32. Thereafter, the process returns to step S202. As a result, the power values P0 to P2 are measured again, the efficiency η is calculated, and the efficiency η and the threshold efficiency ηx are compared. That is, the vehicle-side controller 25 performs variable control of the constant of the second impedance converter 32 until the efficiency η becomes equal to or higher than the threshold efficiency ηx.

  Note that the vehicle-side controller 25 notifies the error and notifies the main charging if the efficiency η does not exceed the threshold efficiency ηx, regardless of the value of the constant of the second impedance converter 32 set. Processing may be terminated.

  When the efficiency η is equal to or greater than the threshold efficiency ηx, the vehicle-side controller 25 makes a positive determination in step S205 and proceeds to step S207. In step S207, the power supply controller 14 determines whether or not the AC power value P2 measured by the output power measuring device 60 is within a predetermined allowable range (Ptmin to Ptmax). The allowable range is a range including the specific power value Pt, and for example, has a predetermined numerical range around the specific power value Pt.

  When the AC power value P2 is within the allowable range, it means that it is not necessary to perform variable control of the constant of the first impedance converter 31. In this case, the power supply controller 14 proceeds to step S210. On the other hand, when the AC power value P2 is outside the allowable range, it is confirmed that the AC power having a desired power value (specific power value Pt) is not output from the power supply unit 12 due to fluctuations in the relative positions of the coils 13a and 23a. means. In this case, the power supply controller 14 makes a negative determination in step S207 and proceeds to step S208. In step S <b> 208, the power supply side controller 14 performs variable control of the constants of the first impedance converter 31.

  Then, the power supply side controller 14 grasps | ascertains AC power value P2 again in step S209. Then, the power supply side controller 14 returns to step S207 and determines again whether or not the AC power value P2 is within the allowable range. That is, the power supply side controller 14 performs variable control of the constant of the first impedance converter 31 until the AC power value P2 falls within the allowable range. In other words, the power controller 14 performs variable control of the constant of the first impedance converter 31 so that the AC power value P2 approaches (preferably matches) the specific power value Pt.

  In addition, even if the power supply side controller 14 is a case where the constant of the 1st impedance converter 31 is set to any value, when the alternating current power value P2 does not fall within the allowable range, an error is notified, This charging process may be terminated.

Next, the operation of this embodiment will be described.
When the efficiency η is less than the threshold efficiency ηx, variable control of the constant of the second impedance converter 32 is performed so that the efficiency η is equal to or higher than the threshold efficiency ηx. When the AC power value P2 is outside the allowable range, variable control of the constant of the first impedance converter 31 is performed so that the AC power value P2 approaches the specific power value Pt.

According to the embodiment described in detail above, the following excellent effects are obtained in addition to the effects (1) to (3).
(5) The non-contact power transmission apparatus 10 includes an output power measuring device 60 that measures the power value (AC power value P2) of AC power output from the power supply unit 12. In such a configuration, the vehicle-side controller 25 performs variable control of the constant of the second impedance converter 32 based on the efficiency η calculated from the primary-side DC power value P0 and the secondary-side DC power value P1. The power supply side controller 14 performs variable control of the constant of the first impedance converter 31 based on the AC power value P2 measured by the output power measuring device 60. Thereby, the AC power of the specific power value Pt can be output from the power supply unit 12 while performing variable control of the constant of the second impedance converter 32 in consideration of the power loss of the DC / AC converter 12b.

  (6) In particular, the variable control of the constant of the first impedance converter 31 is performed after the variable control of the constant of the second impedance converter 32 is performed. Thereby, it is possible to avoid performing useless variable control.

  More specifically, for example, when the variable control of the constant of the first impedance converter 31 is performed and then the constant control of the constant of the second impedance converter 32 is performed, the variable control of the constant of the second impedance converter 32 is performed. The impedance Zp from the output terminal of the power supply unit 12 to the vehicle battery 22 varies. For this reason, the variable control of the constant of the first impedance converter 31 is required again. On the other hand, according to the present embodiment, by performing variable control of the constant of the second impedance converter 32 in advance, the above inconvenience can be avoided and control can be simplified.

In addition, you may change the said embodiment as follows.
In each embodiment, the vehicle-side controller 25 calculates the efficiency η, but is not limited to this. For example, the power supply side controller 14 may calculate the efficiency η. In this case, the vehicle-side controller 25 transmits the secondary-side DC power value P1 to the power supply-side controller 14. Further, a controller other than the controllers 14 and 25 may calculate the efficiency η. In this case, each of the controllers 14 and 25 transmits information on the primary side DC power value P0 and the secondary side DC power value P1 to the other controller. In short, the calculation subject of the efficiency η is arbitrary, and the controllers 14 and 25 may transmit and receive information so that the calculation subject can calculate the efficiency η.

  If the calculated efficiency η is less than the threshold efficiency ηx, the charging process may be terminated by reporting an error without performing variable control of the constants of the impedance converters 31 and 32. That is, as a determination of whether or not to perform power transmission (determination of whether or not to continue power transmission), the calculated efficiency η and the threshold efficiency ηx may be compared.

  In addition to or instead of the second impedance converter 32, a DC / DC converter having a switching element that periodically switches may be provided between the rectifier 24 and the vehicle battery 22. In this case, the DC / DC converter converts the secondary side DC power rectified by the rectifier 24 into the secondary side DC power having a different voltage value and outputs the secondary side DC power to the vehicle battery 22.

  In such a configuration, the impedance from the input end of the DC / DC converter to the vehicle battery 22 depends on the on / off duty ratio of the switching element of the DC / DC converter. Focusing on this point, by adjusting the duty ratio, the impedance from the input end of the DC / DC converter to the vehicle battery 22 may be adjusted according to the fluctuation of the impedance of the vehicle battery 22 and the like. . In this case, the DC / DC converter corresponds to the “impedance converter”. That is, the impedance converter may be between the power receiver 23 and the rectifier 24, or may be between the rectifier 24 and the vehicle battery 22.

  The measurement position of the secondary measuring instrument 50 is the input end of the vehicle battery 22, but is not limited to this, and may be any position from the rectifier 24 to the vehicle battery 22. For example, in the configuration in which the DC / DC converter is provided as described above, the measurement position of the secondary side measuring device 50 may be between the rectifier 24 and the DC / DC converter.

  Each of the impedance converters 31 and 32 includes a plurality of LC circuits having different constants and a relay that can selectively connect an LC circuit to which AC power is transmitted among the plurality of LC circuits. There may be. In this case, the constants of the impedance converters 31 and 32 can be variably controlled by controlling the relay.

  The specific configuration of the LC circuit of each of the impedance converters 31 and 32 is arbitrary, and may be, for example, any of L-type, inverse L-type, π-type, and T-type, or other Good. When a class D amplifier is used as the DC / AC converter 12b, the first impedance converter 31 may be other than the L type. Further, the invention is not limited to the LC circuit, and a transformer or the like may be used, for example.

  In the first embodiment, only the constant variable control of the first impedance converter 31 is performed based on the efficiency η, and the constant control of the constant of the second impedance converter 32 is not performed. Or vice versa. That is, based on the efficiency η, variable control of any one of the impedance converters 31 and 32 may be performed. In this case, an impedance converter that is not subjected to variable control may be omitted.

○ At least one constant of each of the impedance converters 31 and 32 may be a predetermined fixed value.
A plurality of impedance converters may be provided in the power transmission device 11. Similarly, the power receiving device 21 may be provided with a plurality of impedance converters.

O At least one of the impedance converters 31 and 32 may be omitted.
In the first embodiment, in step S106, the vehicle-side controller 25 transmits information on the efficiency η, and the power-source controller 14 performs variable control of the constant of the first impedance converter 31 based on the information. However, it is not limited to this. For example, the vehicle-side controller 25 may determine a constant of the first impedance converter 31 and transmit information related to the determined constant to the power supply-side controller 14. In this case, the power supply side controller 14 changes the constant of the 1st impedance converter 31 based on the information. That is, the vehicle side controller 25 may determine the constants of the impedance converters 31 and 32.

  Similarly, the power supply side controller 14 may determine the constants of the impedance converters 31 and 32, or a controller other than the controllers 14 and 25 may determine the constants. In short, the control subject that performs variable control of the impedance converters 31 and 32 is arbitrary.

  The specific mode of variable control of the constants of the impedance converters 31 and 32 is arbitrary. For example, the controllers 14 and 25 may be configured to sequentially set constants that can be set for the impedance converters 31 and 32.

  In addition, the power supply side controller 14 refers to the map data in which the efficiency η and the constant of the first impedance converter 31 are associated with each other, thereby determining the constant of the first impedance converter 31 that can obtain the desired efficiency η. The constant of the first impedance converter 31 may be set to the derived constant. Similarly, the vehicle-side controller 25 refers to the map data in which the efficiency η and the constant of the second impedance converter 32 are associated with each other, thereby determining the constant of the second impedance converter 32 that can obtain the desired efficiency η. The constant of the second impedance converter 32 may be set to the derived constant.

  In each embodiment, the second impedance converter 32 matches the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 and the impedance from the output terminal of the power receiver 23 to the power supply unit 12. However, it is not limited to this. For example, in the real part of the impedance from the output terminal of the power receiver 23 (secondary coil 23a) to the vehicle battery 22, there is a specific resistance value Rout in which the efficiency η is relatively higher than other impedances. In consideration of this, a constant of the second impedance converter 32 may be set. Specifically, if a virtual load is provided at the input end of the power transmitter 13, if the resistance value of the virtual load is Ra and the resistance value from the output end of the power receiver 23 to the virtual load is Rb, the specific resistance The value Rout is √ (Ra × Rb). The second impedance converter 32 may be configured to perform impedance conversion so that the impedance from the output terminal of the power receiver 23 to the vehicle battery 22 approaches (preferably matches) the specific resistance value Rout.

The voltage waveform of the AC power output from the power supply unit 12 is arbitrary, and may be, for example, a sine wave, a rectangular wave, or the like.
The power supply unit 12 may be any of a voltage source, a current source, and a power source.

In each embodiment, the resonance frequency of the power transmitter 13 and the resonance frequency of the power receiver 23 are set to be the same. However, the present invention is not limited to this, and may be different within a range in which power transmission is possible.
In each embodiment, the power transmitter 13 and the power receiver 23 have the same configuration, but are not limited to this, and may have different configurations.

  In each embodiment, the primary coil 13a and the primary capacitor 13b are connected in parallel. However, the present invention is not limited to this, and may be connected in series. Similarly, the secondary coil 23a and the secondary capacitor 23b may be connected in series.

In each embodiment, the capacitors 13b and 23b are provided, but these may be omitted. In this case, magnetic field resonance is performed using the parasitic capacitances of the coils 13a and 23a.
In each embodiment, magnetic field resonance is used to realize non-contact power transmission. However, the present invention is not limited to this, and electromagnetic induction may be used.

  In each embodiment, the non-contact power transmission device 10 is applied to a vehicle, but is not limited thereto, and may be applied to other devices. For example, it may be applied to charge a battery of a mobile phone.

The vehicle-side controller 25 may calculate a power reduction amount δP (= P0−P1) as a parameter indicating the degree of power loss.
The power transmitter 13 may have a configuration including a resonance circuit including a primary side coil 13a and a primary side capacitor 13b, and a primary side coupling coil that is coupled to the resonance circuit by electromagnetic induction. Similarly, the power receiver 23 may include a resonance circuit including a secondary coil 23a and a secondary capacitor 23b, and a secondary coupling coil coupled to the resonance circuit by electromagnetic induction.

Next, the technical idea that can be grasped from the above embodiment and other examples will be described below.
(A) When the degree of the power loss calculated by the calculation unit is outside a predetermined allowable range, the control unit performs the impedance conversion so that the degree of the power loss is within the allowable range. The non-contact power transmission apparatus according to claim 2, wherein variable control of impedance of the unit is performed.

  (B) As the impedance converter, a first impedance converter provided between the power supply unit and the primary coil, and a second impedance provided between the secondary coil and the load. A conversion unit, wherein the control unit performs variable control of impedances of both the first impedance conversion unit and the second impedance conversion unit based on a calculation result of the calculation unit. The non-contact power transmission device described in 1.

  (C) The impedance converter is a secondary impedance converter provided between the secondary coil and the load, and the contactless power transmission device includes the power supply and the primary coil. A primary-side impedance conversion unit having a variable impedance, and an output power measurement unit that measures a power value of the AC power output from the power supply unit, and the control unit includes: Based on the calculation result of the calculation unit, variable control of the impedance of the secondary side impedance conversion unit is performed, and based on the measurement result of the output power measurement unit, variable control of the impedance of the primary side impedance conversion unit is performed. The contactless power transmission device according to claim 2 or (A).

  DESCRIPTION OF SYMBOLS 10 ... Non-contact electric power transmission apparatus, 11 ... Power transmission apparatus, 12 ... Power supply part, 12a ... AC / DC converter, 12b ... DC / AC converter, 13a ... Primary side coil, 14 ... Power source side controller, 21 ... Power reception Equipment: 22 ... Vehicle battery, 23a ... Secondary side coil, 24 ... Rectifier, 25 ... Vehicle side controller, 31, 32 ... Impedance converter, 40 ... Primary side measuring instrument, 50 ... Secondary side measuring instrument.

Claims (7)

When system power is input from the system power source, the power system unit can convert the system power into AC power having a predetermined frequency and output the power, and
A primary coil to which the AC power is input;
A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil;
A rectifying unit that rectifies AC power received by the secondary coil;
A load to which secondary side DC power rectified by the rectification unit is input;
In a non-contact power transmission device comprising:
The power supply unit includes an AC / DC converter that converts the grid power into predetermined primary DC power, and a DC / AC converter that converts the primary DC power into the AC power. ,
The non-contact power transmission device is
A primary side measurement unit that measures a power value of the primary side DC power input to the DC / AC conversion unit;
A secondary side measurement unit that measures the power value of the secondary side DC power at a predetermined position from the rectifying unit to the load;
Based on the measurement result of the primary side measurement unit and the measurement result of the secondary side measurement unit, a calculation unit that calculates the degree of power loss from the input end of the DC / AC conversion unit to the predetermined position;
A non-contact power transmission device comprising: An impedance converter provided between the power supply unit and the load and having a variable impedance;
Based on the calculation result of the calculation unit, a control unit that performs variable control of the impedance of the impedance conversion unit,
The non-contact electric power transmission apparatus of Claim 1 provided with. The secondary side measuring unit measures the power value of the secondary side DC power at the position of the input end of the load as the predetermined position,
The said calculation part calculates the degree of the power loss from the input terminal of the said DC / AC conversion part to the said load based on the measurement result of the said primary side measurement part, and the measurement result of the said secondary side measurement part. The non-contact electric power transmission apparatus of Claim 1 or Claim 2. When system power is input from the system power source, the power system unit can convert the system power into AC power having a predetermined frequency and output the power, and
A primary coil to which the AC power is input;
A secondary coil that can receive the AC power from the primary coil in a non-contact manner, a rectifier that rectifies the AC power received by the secondary coil, and 2 rectified by the rectifier For a power receiving device having a load to which secondary side DC power is input, in a power transmission device capable of transmitting the AC power in a contactless manner,
The power supply unit includes an AC / DC converter that converts the grid power into predetermined primary DC power, and a DC / AC converter that converts the primary DC power into the AC power. ,
The power transmission device includes a primary side measurement unit that measures a power value of the primary side DC power input to the DC / AC conversion unit,
From the measurement result of the primary side measurement unit and the power value of the secondary side direct-current power at a predetermined position from the rectification unit to the load, from the input end of the DC / AC conversion unit to the predetermined position A power transmission device in which the degree of power loss is calculated. The power transmission device is provided between the power supply unit and the primary coil, and includes an impedance conversion unit whose impedance is variable,
The power transmission device according to claim 4, wherein variable control of impedance of the impedance conversion unit is performed based on the calculated degree of power loss. When system power is input from the system power supply, an AC / DC conversion unit that converts the system power into predetermined primary DC power, and AC power with a predetermined frequency for the primary DC power A power receiving device capable of receiving the AC power in a non-contact manner from a power transmission device including a power source unit having a DC / AC conversion unit for converting to a primary coil to which the AC power is input,
A secondary coil capable of receiving the AC power in a non-contact manner from the primary coil;
A rectifying unit that rectifies AC power received by the secondary coil;
A load to which secondary side DC power rectified by the rectification unit is input;
A secondary side measurement unit that measures the power value of the secondary side DC power at a predetermined position from the rectifying unit to the load;
With
The power from the input end of the DC / AC converter to the predetermined position based on the power value of the primary DC power input to the DC / AC converter and the measurement result of the secondary measurement unit A power receiving device in which a degree of loss is calculated. The power receiving device is provided between the secondary coil and the load, and includes an impedance conversion unit having a variable impedance.
The power receiving device according to claim 6, wherein variable control of impedance of the impedance conversion unit is performed based on the calculated degree of power loss.